1. Field of the Invention
The present invention relates to a monitor of an X-ray radiation range for an object to be radiated.
2. Description of the Prior Art
According to the conventional monitor of an X-ray radiation range, said X-ray radiation range for an object to be radiated can be visually confirmed, that is to say, as shown in for example FIG. 1, an X-ray (a) radiator (1) and a visible ray (c) projector (5) can be moved by the distance equivalent to a pitch (l) between an axis (P) of radiant X-ray and an axis (P.sub.1) of visible ray so that X-rays may be radiated on the desired range of an object to be radiated. At first said visible ray (c) is projected on the desired range of said object (3) to be radiated and then said X-ray radiator (1) is moved so as to set said axis (P) of radiant X-ray to the position where said axis (P.sub.1) of visible ray was placed. X-rays (a) are radiated on the desired range of said object (3) to be radiated by radiating X-rays (a) under this condition.
However, such a conventional monitor means has the following disadvantages:
The projection of visible ray (c) and the radiation of X-rays (a) can not be simultaneously carried out, thereby such a secular change that elements are oxidized during the time when said visible ray projector (5) and said X-ray radiator (1) are changed in positions is produced in the case when said elements contained in various kinds of metal and mineral are analyzed with them as said object (3) to be radiated. In addition, the above described changes of position must be repeatedly carried out at every time when said X-ray radiation range is changed, thereby such a conventional monitor means is remarkably inferior in maneuverability.
Furthermore, according to another conventional monitor means as shown in FIG. 2, an X-ray radiator (1) and a visible ray projector (5) are arranged so that an axis (P) of X-ray may intersect an axis (P.sub.1) of visible ray so as to set the surface of an object (3) to be radiated, on which X-rays are incident, to a point of intersection of said axes (P), (P.sub.1), thereby the radiation of X-rays (a) and the projection of visible ray (c) can be simultaneously carried out and the process of changing X-ray (a) radiation range can be improved. However, even this means has the following disadvantages:
Only an object having a flat surface, on which X-rays are incident, can be used for said object (3) to be radiated. That is to say, as shown in an enlarged scale in FIG. 2, the point, on which X-rays (a) are radiated, and the point, on which visible ray (c) is projected, have a location lag therebetween, when the surface of said object to be radiated, on which X-rays are radiated, is rough, thereby X-rays (a) are radiated on the range beside a visible ray projection range. As a result the radiation of X-rays (a) and the projection of visible ray (c) can be simultaneously carried out but the detecting range of X-rays (a) is different from that of visible ray (c).
The monitor means as shown in FIG. 2 also has such a disadvantage that the radiation range of X-rays (a) is different from that of visible ray (c) owing to a slight location lag between the surface, on which X-rays are radiated, and the point of intersection of X-rays (a) and visible ray (c).